To date, in a wireless communication system, a mobile station has been performing communication with a base station that forms a cell in which the mobile station exists. The mobile station changes a base station to another base station while moving in accordance with the position thereof. However, at the time of design and displacement of a base station, depending on transmission power and direction of an antenna, there may arise an area (hereinafter referred to as a “coverage hole”) in which communication quality of any base station does not reach a value that is allowed to communicate with the mobile station. In order to detect a coverage hole, for example, a method described below is employed. First, a designer of a base station divides an area to be determined whether there is a coverage hole or not into a plurality of grids (sub-areas), and sets up one evaluation point in each of these grids. Next, the designer measures communication qualities of neighboring base stations at each of the evaluation points. If none of the communication qualities of the neighboring base stations satisfy a demanded condition, a grid in which the evaluation point exists is determined to be a coverage hole.
However, if a determination target area of the coverage hole expands to a wide area, or if an area of a grid (granularity) is made small in order to increase detection precision, the designer arranges a lot of evaluation points. As a result, there is a problem in that the number of evaluation points at which communication qualities of the base stations increases, and an amount of calculation of CINR (Carrier to Interference and Noise Ratio) values that has to be performed for coverage hole detection increases. Such a problem becomes obvious in the case where a lot of neighboring base stations are located in the vicinity of an evaluation point. In particular, numbers of microcells and femtocells increase in recent years, thus a cell size of a base station is reduced, and thereby a coverage hole is reduced in size. Accordingly, in order for a designer to increase detection precision, the designer has to make the grid small, and to set up a larger number of the evaluation points. The above-described amount of calculation further increases in accordance with this.
Related-art techniques have been disclosed in International Publication Pamphlet No. WO 2009/060935, and Japanese Laid-open Patent Publication No. 2011-44808.